Reverse Osmosis Membrane Testing

HOW TO TAKE A WATER SAMPLE

Have two clean plastic bottles available. We need at least 1-2 ounces. An Aquafina water bottle, for example, works fine. Do not use salt shakers, medicine bottles, etc.

Run the regular tap water for 1 minute. Rinse the bottle twice with the tap water. Slow down the flow and fill the bottle all the way to the top. As you are closing the lid on the bottle, squeeze the bottle a little so that air is purged as you are sealing the bottle. Air and time degrade this water sample.

Run the reverse osmosis water for 1 minute. Rinse the bottle twice with the reverse osmosis (RO) water. Fill the bottle all the way to the top. As you are closing the lid on the bottle, squeeze the bottle a little so that air is purged as you are sealing the bottle.

VERY IMPORTANT: Place an address label or write your name, address, date, and phone on the bottle. We get water samples in all the time – so without identification we do not perform the water test. Please note the condition of the sample (discolored, smelly, etc.) and the date collected.

Bring in or send the sample to the address listed at the top of this page as soon as you can. Old samples are simply dumped. We will not send your container back but we will recycle.

This test is for RO membrane rejection and measures the amount of total dissolved solids (TDS) in each sample. We compare the two numbers to determine how well the membrane is functioning. In general, a membrane is functioning properly if it is rejecting at least 80% of the dissolved solids in the water.

This test is not measuring the safety of the water or the amount of microcystin, only the TDS.